1. Field of the Invention
The present invention relates to a signal processing device and a control method, a signal processing method, a program, and a signal processing system. More specifically, the present invention relates to a signal processing device and a control method, a signal processing method, a program, and a signal processing system, which make it possible to perform stable control of controlled units even when the number of controlled units increases.
2. Description of the Related Art
In signal processing systems according to the related art, a control unit that controls a plurality of signal processing units is connected to each of the signal processing units via a non-high-speed communication path used exclusively for control purposes (hereinafter, referred to as control line as appropriate), thus controlling the signal processing units. This configuration is appropriate for cases where the processing capacity or communication bandwidth of the control unit is sufficiently large relative to the number of signal processing units that are controlled units.
For example, the following system has been proposed (see, for example, Japanese Unexamined Patent Application Publication No. 6-96001). In the system, a bus is connected in a loop to a control unit including a write interface unit for the write direction and a read interface unit for the read direction, in such a way that the bus makes a loop from the write interface unit to the read interface unit. One or more controlled units are connected to this bus. A signal sent out to the bus from the write interface unit of the control unit is received by the controlled units, and in response to this, the corresponding controlled unit sends out a signal to the read interface unit of the control unit via the bus.
In the case of adding a signal processing unit additionally in the signal processing system described above, each time a signal processing unit is added, the volume of control information to be supplied from the control unit to the signal processing units increases, so the load on the control unit increases, and spare bandwidth decreases. As a result, the processing capacity or communication bandwidth of the control unit becomes insufficient, so there is even a risk of breakdown of control in the signal processing system.
Accordingly, to avoid breakdown of control in the signal processing system as described above, it is generally conceivable to enlarge the bandwidth of the control line, or increase the processing capacity of the control unit.